title: Genomic DNA cloning of the region encoding nitric oxide reductase in Paracoccus halodenitrificans and a structure model relevant to cytochrome oxidase.
abstract: The structural genes for the NO reductase in Paracoccus halodenitrificans, norC, norB, and norQ were sequenced. The norC and norB encode the cytochrome c (NorC) and cytochrome b (NorB) subunits, respectively. The matured NorC (17,258 Da, 148 residues) has a binding motif (CXYCH) for heme c, which is axially coordinated by His65 and Met115. NorB (52,337 Da, 451 residues) has twelve putative transmembrane helices and the 19% sequence homology with the subunit I of cytochrome oxidase from Paracoccus denitrificans. Several histidine and glutamate residues were identified as the ligands for two hemes b and a non-heme iron in comparison with the sequence of cytochrome oxidase. The higher-order model structures constructed from the amino acid sequences of NorC and NorB showed the topology of the helical segments and the locations of the metal centers.
authors.affiliation: Institute for Molecular Science, Okazaki National Research Institutes, Okazaki, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Sakurai
authors.forename: T
authors.initials: T
authors.lastname: Sakurai
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry; D001665:Binding Sites; D003001:Cloning, Molecular; D017124:Conserved Sequence / Q000235:genetics; D003576:Electron Transport Complex IV / Q000737:chemistry; D019143:Evolution, Molecular; D006418:Heme / Q000031:analogs & derivatives / Q000378:metabolism; D010088:Oxidoreductases / Q000737:chemistry*; D010230:Paracoccus / Q000201:enzymology*; D011485:Protein Binding; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
chemical_list: D001426:Bacterial Proteins; C031690:heme C; D006418:Heme; D010088:Oxidoreductases; C059847:nitric acid reductase; D003576:Electron Transport Complex IV